• Mycobiology
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• 제50권1호
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• pp.79-85
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• 2022

Strawberries are a popular economic crop, and one of the major plantations and exporting countries is Korea in the world. The Fusarium oxysporum species complex (FOSC) is a soil-borne pathogen with genetic diversity, resulting in wilt disease in various crops. In Korea, strawberries wilt disease was first reported in the 1980s due to the infection of FOSC, causing significant economic damage every year. The causal agent, F. oxysporum f. sp. fragariae, is a soil-borne pathogen with a characteristic of FOSC that is difficult to control chemically and mutates easily. This study obtained genetic polymorphism information that was based on AFLP, of F. oxysporum f. sp. fragariae 91 strains, which were isolated from strawberry cultivation sites in Gyeongsangnam-do and Chungcheongnam-do, and compared strains information, which was the isolated location, host variety, response to chemical fungicide, and antagonistic bacteria, and mycelium phenotype. As a result, AFLP phylogeny found that two groups were mainly present, and group B was present at a high frequency in Gyeongsangnam-do. Group B proved less sensitive to tebuconazole than group A through Student's t-test. In addition, the fractions pattern of AFLP was calculated by comparing the strain information using PCA and PERMANOVA, and the main criteria were separated localization and strawberry varieties (PERMANOVA; p< 0.05). And tebuconazole was different with weak confidence (PERMANOVA; p< 0.10). This study suggests that the F. oxysporum f. sp. fragariae should be continuously monitored and managed, including group B, which is less chemically effective.

• 대한의생명과학회지
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• 제12권2호
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• pp.119-125
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• 2006

In relation to the tissue engineering, the cellular responses to the morphology of the scaffold surface are interesting topics. Human ligament fibroblasts (HLFs) were cultured on the micrpatterned silicone substrates subjected to cyclic stretch to simulate ligament motion. Groove and ridge width of silicone substrates was 10/50, 20/50, 20/10, and 20/20 ${\mu}m$ (groove/ridge ${\mu}m$) with a depth of $3{\mu}m$. Strain was applied over two days for 4 hours per day with a frequency of 0.5 Hz with the magnitudes of 4 or 8%. The purpose of this study was to evaluate ligament fibroblast alignment and cellular responses in relation to the pattern of microgrooved surface and stretching magnitude. Ligament fibroblasts in the microgrooved surface were elongated and aligned parallel to the microgrooves under no stretch. Uniaxial cyclic stretch induced cellular activities and their orientation rise in cellular response and the cells showed alignment and elongation perpendicular to the direction of the stretch. Biochemical analyses showed that the best cellular response was found on the $20/50{\mu}m$ under 8% stretch. The surface morphology and mechanical stretching were found to contribute to increase of proliferation, collagen production.

• Earthquakes and Structures
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• 제5권2호
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• pp.161-205
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• 2013

We study seismically induced, anti-plane strain wave motion in a non-homogeneous geological region containing tunnels. Two different scenarios are considered: (a) The first models two tunnels in a finite geological region embedded within a laterally inhomogeneous, layered geological profile containing a seismic source. For this case, labelled as the first boundary-value problem (BVP 1), an efficient hybrid technique comprising the finite difference method (FDM) and the boundary element method (BEM) is developed and applied. Since the later method is based on the frequency-dependent fundamental solution of elastodynamics, the hybrid technique is defined in the frequency domain. Then, an inverse fast Fourier transformation (FFT) is used to recover time histories; (b) The second models a finite region with two tunnels, is embedded in a homogeneous half-plane, and is subjected to incident, time-harmonic SH-waves. This case, labelled as the second boundary-value problem (BVP 2), considers complex soil properties such as anisotropy, continuous inhomogeneity and poroelasticity. The computational approach is now the BEM alone, since solution of the surrounding half plane by the FDM is unnecessary. In sum, the hybrid FDM-BEM technique is able to quantify dependence of the signals that develop at the free surface to the following key parameters: seismic source properties and heterogeneous structure of the wave path (the FDM component) and near-surface geological deposits containing discontinuities in the form of tunnels (the BEM component). Finally, the hybrid technique is used for evaluating the seismic wave field that develops within a key geological cross-section of the Metro construction project in Thessaloniki, Greece, which includes the important Roman-era historical monument of Rotunda dating from the 3rd century A.D.

• 국제초고층학회논문집
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• 제4권1호
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• pp.9-25
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• 2015

Field measurements of various structures have been conducted for many purposes. Measurement data obtained by field measurement is very useful to determine vibration characteristics including dynamic characteristics such as the damping ratio, natural frequency, and mode shape of a structure. In addition, results of field measurements and modal identification can be used for modal updating of FEM analysis, for checking the efficiency of damping devices and so on. This paper shows some examples of field measurements and modal identification for structural health monitoring. As the first example, changes of dynamic characteristics of a 15-story office building in four construction stages from the foundation stage to completion are described. The dynamic characteristics of each construction stage were modeled as accurately as possible by FEM, and the stiffness of the main structural frame was evaluated and the FEM results were compared with measurements performed on non-load-bearing elements. Simple FEM modal updating was also applied. As the next example, full-scale measurements were also carried out on a high-rise chimney, and the efficiency of the tuned mass damper was investigated by using two kinds of modal identification techniques. Good correspondence was shown with vibration characteristics obtained by the 2DOF-RD technique and the Frequency Domain Decomposition method. As the last example, the wind-induced response using RTK-GPS and the feasibility of hybrid use of FEM analysis and RTK-GPS for confirming the integrity of structures during strong typhoons were shown. The member stresses obtained by hybrid use of FEM analysis and RTK-GPS were close to the member stresses measured by strain gauges.

• 대한한방종양학회지
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• 제3권1호
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• pp.67-84
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• 1997

Bujeonghangamtang(扶正抗癌湯) has been used for cure of tumor as a traditional medicine without any experimental evidence to support the rational basis for its clinical use. This study was carried out to evaluate the possible therapeutic or antitumoral effects of Bujeonghangamtang extract against tumor, and to carry out some mechanisms responsible for its effect. Some kinds of tumor were induced by the typical application of 3-methylcholanthrene. (MCA) or by the implantation(s.c) of malignant tumor cells such as leukemia cells(3LL cells) or sarcoma cells(Sl80 cells). Treatment of the Bujeonghangamtang water-extract (dailly 1mg／mouse, i. p.) was continued for 7 days prior to tumor induction and after that the treatment was lasted for 20 days. Against squamous cell carcinoma induced by MCA, Bujeonghangamtang decreased not only the frequency of tumor production but also the number and the weight of tumors per tumor bearing mice (TBM). Bujeonghangamtang also significantly suppressed the development of 3LL cell and S180 cell-implanted tumors in occurrence-frequency and their size, and some developed tumors were regressed by the continuous treatment of Bujeonghangamtang extract into TBM. In vitro, treatment of Bujeonghangamtang extract had no effect on the growth of some kinds of cell line such as FsaII, A431 strain but significantly inhibited the proliferation of 3LL, S180 cells and augmented the DNA synthesis of mitogen-activated lymphocytes. Bujeonghangamtang also stimulated the migrative ability of leukocyte, the MIF and IL-2 production of T lymphocytes, but not IL 6 production of B cells. Bujeonghangamtang-administration to mice enhanced NK cells activities. These results demonstrated that Bujeonghangamtang extract exhibited a significant prophylactic benefits against tumors and its antitumor activity was manifested depending on the type of tumor cells. And these results also suggested that effect of Bujeonghangamtang might be chiefly due to nonspecific enhancement of NK cell activities and cell-mediated immune responses.

• 대한한의학방제학회지
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• 제5권1호
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• pp.147-168
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• 1997

Tish study was carried out to evaluate the possible therapeutic or antitumoral effects of Takrisodokyeum extract against tumor, and immunomodulatory effect. Some kinds of tumor were induced by the typical application of 3-methylcholanthrene (MCA) or by the implantation(s.c) of malignant tumor cells such as leukemia cells(3LL cells) or sarcoma cells(S-I80 and Fas II cells). Treatment of the Takrisodokyeum water-extract(daily 1mg mouse, i.p.) was continued for 7 days prior to tumor induction and after that the treatment was lasted for 15 days. Against squamous cell carcinoma induced by MCA, Takrisodokyeum decreased not only the frequency of tumor production but also the number and the weight of tumors per tumor bearing mice (TBM). Takrisodokyeum also significantly suppressed the development of 3LLcell and S-180 cell by frequency and their size, and some developed tumors were regressed by the continuous treatment of Takrisodokyeum extract into TBM. However, when tumor was induced by FsaII cell-implantation, the growth of implanted cells in mice was delayed by the water extract of Takrisodokyeum until day 7 and then rapid growth ensued. In vitro, treatment of Takrisodokyeum extract had no effect on the growth of some kind of cell lines such as FsaII, A-131 strain but significantly inhibited the proliferation of 3LL, S-180 cells. Takrisodokyeum also stimulated the migrative ability of leucocyte, the MIF and IL 2-production of T lymphocytes, but not IL 6 production of B cells. Takrisodokyeum enhanced Arthus reaction and DTH to sheep erythrocytes, and NK cells activities. These results demonstrated that Takrisodokyeum extract different results according to the type of tumor cells. And these results also suggested that antitumor effect of Takrisodokyeum might be chiefly due to nonspecific enhancement of NK cell activities and cell-mediated immune responses.

• 식물조직배양학회지
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• 제21권5호
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• pp.315-318
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• 1994

CaMV35S promoter-$\beta$-glucuronidase (GUS) 유전자와 선발 표지로서 neomycin phosphotransferase 유전자를 가진 pBI121 binary 벡터를 도입한 Agrobacterium turmfaciens LAB4404와 더덕 유식물체의 자엽 절편을 1 mg/L BA가 첨가된 MS 배지에서 48시간 동안 공동배양한 후 1 mg/L BA, 250 mg/L carbenicillin 100 mg/L kanamycin sulfate을 첨가한 고체배지에 옮겨 명조건에서 배양하였다. 배양 2주 후 절편의 절단면 부근으로부터 수많은 부정아가 형성되기 시작하였다. 이들 부정아의 GUS 활성을 조사한 결과 15%가 양성반응을 나타내었다. 배양 6주 후 절편이 형성한 수많은 부정아로부터 56.7% 빈도로 shoot이 발달하였다. 이들 shoot은 기본배지에 옮겨서 4주 경과되었을 때 대부분 발근하였으며, 재분화된 개체는 토양에 이식하였다. Southem 분석결과 GUS양성을 보인 재분화 개체의 게놈 DNA에 GUS 유전자가 삽입되었음이 확인되었다.

• 한국소음진동공학회논문집
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• 제18권11호
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• pp.1157-1169
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• 2008

This paper presents spectral element formulation which approximates Lamb wave propagation by PZT transducers bonded on a thin plate. A two layer beam model under 2-D plane strain condition is introduced to simulate high-frequency dynamic responses induced by a piezoelectric (PZT) layer rigidly bonded on a base plate. Mindlin-Herrmann and Timoshenko beam theories are employed to represent the first symmetric and anti-symmetric Lamb wave modes on a base plate, respectively. The Euler-Bernoulli beam theory and 1-D linear piezoelectricity are used to model the electro-mechanical behavior of a PZT layer. The equations of motions of a two layer beam model are derived through Hamilton's principle. The necessary boundary conditions associated with the electro-mechanical properties of a PZT layer are formulated in the context of dual functions of a PZT layer as an actuator and a sensor. General spectral shape functions of response field and the associated boundary conditions are obtained through equations of motions converted into frequency domain. Detailed spectrum element formulation for composing the dynamic stiffness matrix of a two layer beam model is presented as well. The validity of the proposed spectral element is demonstrated through numerical examples.

• 한국구조물진단유지관리공학회 논문집
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• 제14권5호
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• pp.179-186
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• 2010

한 구조물이 손상을 입으면 그 구조물의 동적응답(고유진동수, 가속도, 변형률)이 변하게 된다. 이와 같이 변하는 동적응답을 응답신호로 계측하고 이들 데이터를 신경망에 적용하여 구조물의 손상을 평가하는 방법이 신경망손상평가법이다. 현재까지 정형화된 특정한 경우의 연구가 주로 이루어져 있지만 일반적인 신경망손상평가법의 특성에 관한 연구나 실용 가능성과 장단점에 관한 충분한 연구가 부족하다. 따라서 본 연구는 신경망에 다양한 동적응답을 적용하는데 있어 신경망손상평가법의 일반적인 특성과 적용의 문제점을 연구하였다. 신경망손상평가법은 일정한 가진력을 손상이 있는 구조물에 가하고 그로부터 얻은 응답신호를 이용하여 신경망을 학습을 시킨 후, 임의의 손상이 있는 구조물에 동일한 가진력을 가하여 얻은 응답신호를 이용하여 손상의 위치와 정도를 찾는 것이 현재까지의 연구였다. 그러나 일반적으로 구조물에 작용하는 가진력은 일정하지 않다. 따라서 동일한 가진력에 의해 학습된 신경망에 가진력의 변화가 있는 경우에도 손상을 파악하는지 평가하였다. 모든 응답신호는 모형실험을 통하여 획득하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.756-759
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• 2004

We present a piezoelectric actuator using stiffness control and stroke amplification mechanism in order to make large lateral displacement. In this work, we suggest stiffness control approach that generates lateral displacement by increasing the vertical stiffness and reducing the lateral stiffness using additional structure. In addition, an additional structure of a serpentine spring amplifies the lateral displacement like leverage structure. The suggested lateral PZT actuator (bellows actuator) consists of serpentine spring and PZT/electrode layer which is located at the edge of the serpentine spring. The edge of the serpentine spring prevents the vertical motion of PZT layer, while the other edge of the serpentine spring makes stroke amplification like leverage structure. We have determined dimensions of the bellows actuator using ANSYS simulation. Length, width and thickness of PZT layer are 135$\mu$m, 20$\mu$m and 0.4$\mu$m, respectively. Dimensions of the silicon serpentine spring are thickness of 25$\mu$m, length of 300$\mu$m, and width of 5$\mu$m. The bellows actuator has been fabricated by SOI wafer with 25$\mu$m-top silicon and 1$\mu$m-buried oxide layer. The bellows actuator shows the maximum 3.93$\pm$0.2$\mu$m lateral displacement at 16V with 1Hz sinusoidal voltage input. In the frequency response test, the fabricated bellows actuator showed consistent displacement from 1Hz to 1kHz at 10V. From experimental study, we found the bellows actuator using thin film PZT and silicon serpentine spring generated mainly laterally displacement not vertical displacement at 16V, and serpentine spring played role of stroke amplification.